1. Technical Field
The invention relates to a method and apparatus for joining roofing membranes by press-welding overlapped heated edges of the membrane sheets together to form a sealed seam and then testing the integrity of the formed seam with a single tool.
2. Background Information
Sheets of roofing membrane are commonly used in many industrial and commercial roofing applications wherein large sheets of a waterproof membrane, are overlapped and then heated and pressed together to form a heat weld. These sheets are usually an elastomeric-type of material such as various rubber compositions, or thermoplastic sheets and the like. When done properly this method forms a strong water impervious seam which prevents subsequent peeling apart of the seam and prevents the penetration of water. Various types of devices have been developed for initially heating the edges of the overlapped membrane sheets, such as power propelled roller mechanisms which move along the seam and applies pressure to the overlapped sheets with a following roller. These machines work well for long flat seams but cannot function around many protrusions present on a roof.
In another type of apparatus and method, an installer using a hand-held heat gun such as disclosed in U.S. Pat. No. 4,894,112, presses the heated overlapped membrane sheets together by use of a hand roller which is moved along the heated edges. This manual heating of the overlapping membrane edges followed by the subsequent roller pressure applied thereto, is used at various locations on a roof, especially to form the overlapping joints around various protrusions and joints which occur on a roof such as around skylights, ducts, overhanging locations, corners, etc. It has been found that the locations around such protrusions and joints are more time-consuming to do properly and are more difficult to form the water impervious seam than in the flat straight seams. Thus, such seams and joints almost always will be formed with hand-held roller and hand-held heat applying gun.
The installer immediately after forming the heat welded seam, tests the integrity of the seam by using a separate pick tool. This tool usually includes a handle and a rigid rod extending outwardly therefrom and has a bent end, which is moved along the formed seam. If the seam is not formed correctly, the pick end will bite into the seam informing the installer that the seam is defective and will not pass inspection. However, in order to perform this seam testing, the operator is required to constantly manually replace the roller or heat gun with the seam testing tool. This requires constant manipulation and placing of one or both of the installation tools on the roof and picking up and using the seam testing tool during a roof membrane installation. This increases the time required for testing the seams and occasionally will result in the roof installer not correctly checking the roof seams which later will leak or not pass inspection.
Also, another problem is that if an improper seam is not immediately detected, the heated and softened elastomeric or thermoplastic material will harden and cannot be satisfactorily reheated and resealed requiring a subsequent hot patch to be placed thereon. Thus, if an improper seam can be detected immediately by the membrane installer, it can be immediately pressed together avoiding the use of a subsequent patch having to be applied thereto.
Therefore, the need exists in the roofing industry to provide a hand tool and method of use which enables an installer to press together heated overlapped heated edges of membrane sheets by moving a roller over the edges to form a seam, immediately followed by testing the seam with a pick-like tool without requiring the installer to continually manipulate several tools.